-bash-3.00$ sudo zpool status -v
  pool: nerdy
 state: ONLINE
status: One or more devices has experienced an error resulting in data
        corruption.  Applications may be affected.
action: Restore the file in question if possible.  Otherwise restore the
        entire pool from backup.
   see: http://www.sun.com/msg/ZFS-8000-8A
 scrub: scrub completed with 1 errors on Tue Nov 21 18:16:25 2006
config:

        NAME        STATE     READ WRITE CKSUM
        nerdy       ONLINE       0     0     2
          mirror    ONLINE       0     0     2
            c0d0s7  ONLINE       0     0     6
            c3d0s7  ONLINE       0     0     9

errors: The following persistent errors have been detected:

          DATASET  OBJECT  RANGE
          21       40fd9   lvl=0 blkid=24